Management of a large portfolio of real estate properties can present significant challenges, particularly when the number of properties is in the hundreds or thousands. For example, the managers of the portfolio may have objectives that are at least potentially in conflict with each other. To illustrate this with an example, an objective of increasing the amount of gains generated from selling properties may conflict with an objective of maintaining the amount of rental income produced from the portfolio. This conflict in objectives may arise with respect to a given property in that selling the property may provide the advantage of generating a gain, but may have the disadvantage of depriving the portfolio of rental income produced by the property. Moreover, real properties and/or the portfolio as a whole may be financially evaluated according to a number of different measurements, and improving the health of the portfolio with respect to some measurements may cause declines in other measurements of the portfolio's financial health.
The foregoing issues can be generalized as being applicable to other types of portfolios of assets. In general, like real properties, many types of assets or other items may be measured in terms of numerical performance measures, and actions taken with respect to the assets/items in a portfolio may have consequences that enhance some measured aspects of a portfolio while causing other measured aspects to decline. When the number of assets/items in a portfolio (or potentially available for inclusion in a portfolio) is large, there may be great difficulties in determining how best to make trade-offs inherent in conflicting sets of objectives.